“…ℎ = 2,3, … , 𝑛𝑛, where h and n are the forecasting horizon and the number of out-of-sample time series data. Therefore, the forecasting horizons that have been applied in the study are 2, 3, 4, 5, 7, 10, 15, 20, 25, 30 and 45-days ahead of the overnight IIR [6][7] and [16][17][18][19]. Consequently, a (1 − 𝛼𝛼)100% PIs for h-step ahead forecasting and 𝑎𝑎 𝑡𝑡 follows normal distribution is given by Equation 11.…”